Air exhauster



June 7, 1932- G. l. ROCKWOOD ET AL 1,861,817

AIR EXHAUSTER Filed May 26, 1930 2 Sheets-Sheet l Patented June 7, 1932 UNITED STATES PATENT Pies GEORGE I. ROOKWOOD AND HJALMAR G. CARLSON, OF WORCESTER, MASSACHUSETTS, ASSIGNORS TO ROCKVI'OOD SPRINKLER COMPANY OF MASSACHUSETTS, OF WOROES- TEE, IVIASSAOHUSETTS, A CORPORATION OF MASSACHUSETTS AIR, EXHAUSTER Application filed May 26, 1930. Serial No. 455,618.

This invention relates to mechanism for accelerating the escape of air from the distributing or service pipes of a dry pipe sprinkler system. In such systems, a large 3 dry pipe valve normally shuts off the Water supply from the service pipes leading to the sprinklers. The dry pipe valve is held closed by a substantial air pressure maintained in the dry pipe system.

W'hen a sprinkler head opens, air escapes and the air pressure falls in the dry pipe system. lVhen the pressure is sufficiently reduced, the dry pipe valve is opened by the water pressure in the supply pipe and water is thus admitted to the sprinkler. system. Such dry pipe systems are Widely usedwhere the service pipes are exposed to freezing temperatures.

The dry pipe system above described is sometimes found unsatisfactory on account of cation of Emil Benson, Serial Number 399,-

061, filed October 11, 1929, and comprises a relatively large vent valve designed to be opened as soon as a slight drop in pressure 111 the service pipes is caused by the openlng V of a sprinkler head. These air exhausters depend for their efiective operation upon the development of a difference in pressure between the body of air confined at one side of a diaphragm or other similar structure and the air in the dry pipe system which engages the other side of the diaphragm or structure.

It is necessary to prevent the vent valve of the air exhauster from being opened by a gradual drop in dry pipe pressure caused by leakage. Accordingly, a very small passage or bleed opening has been provided through which air may filter slowly from one side to the other of the diaphragm, thus equalizing the pressure and preventing the opening of the vent valve in the exhauster'unless the fall in pressure in the dry pipe system is so: abrupt that the pressures on opposite sides of the diaphragm cannot be kept equalized by the liow ofair through the very. small bleed opening.

Ditficulty has been encountered in the use of such bleed openings or weep holes, as they are necessarily of extremely small cross section and easily become clogged by particles of dust or dirt or by any slight corrosion. It also required a long time to equalize the pres sure through such a small opening when a dry pipe system is placed under air pressure, and until such equalizing is effected, the air exhauster is inoperative.

It is the object of our invention to substitute an improved valve mechanism for the bleed opening or Weep hole in an air exhauster, by Which substitution the disadvantages above outlined are entirely avoided.

A further object is to provide a construction in an air exhauster by whichran air passage of substantial cross section is normally open to connect the opposite sides of the diaphragm or other air-controlled structure, and to further provide for promptly clos ing said air passage upon the occurrence of an abrupt fall of air pressure in the sprinkler system. 7

Our invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in Which Fig. 1 is a sectional front elevation of our improved air exhauster; and

Figs. 2, 3 and 4 are enlarged sectional front elevations ofour improved relief valve, showing the .same under different operative conditions.

Referring to the drawings, we have showna portion of a Water supply pipe 10, a portion of the distributing or service pipes 11,

and a portion of the casing 12 of a dry pipe v chamber 20 connected through a passage 21 to the valve 16 and passage 17 previously described. A screen 22 may be interposed between the chamber 20 from the passage 21. The chamber 20 is provided with a relatively large vent valve 24, covering an atmosphere port 25. The valve 24 is adjustably mounted on a lever 26 pivoted at 27 in the casing of the upper chamber 20. The free end of the lever 26 is pivotally connected to a vertically moving rod or plunger 30, supported at its lower end on a diaphragm 3:1 and having an axial air passage 32 extending through the same.

The diaphragm 31 extends across an air chamber 33 which normally contains air at the same pressure as the air in the distribuing or service pipes. At its lower end the chamber 33 is provided with a vent valve 34, normally pressed downward and closed by a spring 35.

The valve 34 covers a port 36, opening into a small auxiliary casing 37 which is connect.- through a vent pipe 38 to the atmosphere. The casing 37 also contains a sylphon 40 which closes the upper end of a pipe 41 which is so connected to the sprinkler system that it will be filled with water under pressure as soon as the dry pipe valve 12 opens.

W'hen the pipe 41 is thus filled with water, the sylphon 4O expands, engaging the lower end of the valve rod 42 of the valve 34 and lifting the valve from its seat, thus venting the chamber 33 to the atmosphere.

The parts thus far described are'in general of a usual construction and taken bythemselves constitute no part of our present invention, which relates particularly to im-, proved devices for controlling the commu-, nication between the upper air chamber 20 and the passage 32 in the plunger 30.

Referring to Fig. 2, a casingmember 44 is mounted on the upper end of the plunger 30 and the casing is provided with a cover 45 threaded thereon. A light flexible diaphragm 47 is clamped at its edges between the casing 44 and cover 45. A port member 48 is clamped to the middle portion of the diaphragm 4'7 and is provided with an axial port opening 50.

An upwardly projecting ring or flange 51 on the casing 44 limits downward movement of the port member 48 and a similar ring or flange on the cover 45 limits upward movement of the member 48. The space'between the diaphragm 47 and the cover 45 is vented to the chamber 20 through an opening 53.

A valve 55 is supported in the cover 45, with its valve stem 56 extended downward into the opening 50 in the port member 48. The valve 55 is provided with an enlarged upper end portion 57 seated on a flange 58,

of the cover 45 and thus limiting downward movement of the valve. The valveis yieldingly held in the position shown in Fig. 2 by a spring 60 confined by a cap 61 threaded on an upper portion of the cover 45. A similar valve 64 is mounted at the lower end of the passage 50 in the port member 48 and is seated against a flange 65 in the casing 44 by a spring 66.

When the parts are in normal position, the port member 48 is positioned midway between the valves 55 and 64 and both valves are spaced from their seats to provide a free air passage between the two sides of the diaphragm 47. The port member 48 is thus positioned by a coil spring which is of limited expansion and is of just the right length to support the member 48 in mid-position.

There is a tree passage from the casing 44 through openings in the head of the valve 64 to the upper end of the passage 32, which in turn communicates with the air chamber 33 previously described. The pressure in the upper air chamber 20 and in the lower air chamber 33 (Fig. 1) is thus balanced and is maintained at the same pressure as in the dis tributing pipes.

When a sprinkler opens, the pressure in the upper chamber 20 drops more quickly than the pressure in the lower chamber 33 and the diaphragm 47 is pushed upward with an abrupt or pull action. This movement causes the valve 55 to close the upper end of the passage 50 in the port member 48 and no turther escape of air from the lower chamber 33 can take place.

The difference in pressure on the two sides of the large lower diaphragm 31 then increases rapidly and the pressure on the diaphragm 31 quickly acts through the lever 26 to. open the vent valve 24 and vent the service pipes through the large port opening 25.

As the port member 48 moves upward, it engages the flange 52 previously described, which prevents. further upward. movement and thus prevents excessive pressure on. the valve 55 or its seat in the member 48.

hen the pressure in the dry pipe system is sufliciently reduced, the dry pipe valve will open, admitting water tothe system and also tothe-pipe'41 (Fig. 1) whichwill cause the lower vent valve 34 to be opened, reducing the. pressure in the chamber 33' to atmospheric and permitting the water pressure above the diaphragm 31 to. press the diaphragm down- Ward,'seating-the vent valve 24 and preventing escape of water tothe atmosphere through the port 25.

We then have the condition indicated in Fig. 4, with atmospheric'pressure in the passage 32 and with the upper chamber 20 filled with water under pressure. A certain amount of this water flows through the opening'52 into the space between the diaphragm 47and the cover 45, and would flow past the valve55 through the passage 50 to the passage32andto the lower air chamber 33 if it were not for the provision of the lower valve Get.

As the water pressure depresses the diaphragm 47, the lower end of the port member 48 engages the valve 64, thus closing the passage 50 and preventing any substantial flow of water into the passage 32. The downward movement of the port member 48 is limited by the flange 51 previously described.

In the position shown in Fig. 3, the spring is inoperative but in the position shown in Fig. 4-, the spring 70 is slightly compressed by the downward movement of the member 48 and assists in raising the valve when the pressure thereon is reduced. I It will thus be seen that we have provided a construction by which we avoid the use of minute bleed openings or weep holes which may be easily clogged by dust or dirt. In place thereof we use the passage 50 of substantial cross section with normally open valves at each end of the passage.

The use of the valves in place of bleed openings has other important advantages. It prevents the escape of air from the chamber 33 to the chamber 20 as soon as the valve 55 is closed and thus more quickly develops a difference in pressure sufficient to operate the lower diaphragm 81 and open the vent valve 2%. Furthermore, a very important advantage resides in the greatly increased speed with which the pressure in the chamber 33 is built up to dry pipe pressure when the service pipes are drained and again filled with air under pressure. With the bleed opening or weep hole. the transfer of air was so slow that the air exhauster was inoperative for a considerable period after resetting, before the air pressures became equalized so that the device attained normal operative condition.

Having thus described our invention and the advantages thereof, we do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what we claim is 1. In an air exhauster for a dry' pipe system, a yielding member exposed at one side to dry pipe pressure, a vent valve controlled a to said chamber and to thereby equalize the second yielding member being exposed at one side to dry pipe pressure and at the other side to the pressure in said chamber.

2. The combination in an air exhauster as set forth in claim 1, in which the second valve is mounted to yield when engaged by its port member.

3. The combination in an air exhauster as set forth in claim 1, in which the second valve is mountedto yield when engaged by its port member and in which meansindependent of the second valve is provided for limiting the travel of said port member and second valve. y

4. The combination in an air exhauster as set forth in claim 1, inwhich a third valve is provided to additionally control the connection to said chamber,'and in which-move ment of said second yielding member and said port member by substantial excess pressure in said dry pipe system causes said port member to engage said third valve, whereby said port and passage are'closed.

5. The combination in an air exhauster as set forth in claim 1, in which a third valve is provided to additionally control the connection to said chamber, and in which move ment of said second yielding member and said port member by substantial excess pressure in said dry pipe system causes" said port member to engage said third valve, whereby said port and passage are closed, said second and third valves being each mounted to yield when engaged by said port member.

6. The combination'in an air exhauster as set forth in claim 1, in which a third valve is provided to additionally control the connection to said chamber and in which movement of said second yielding member and said port member by substantial excess pres sure in said dry pipe system causes said port member to engage said third valve, whereby said port and passage are closed, said second and third valves being each mounted to yield when engaged by said port member, and means independent of said second and third valves being provided to limit travel of said port member.

7 In an air exhauster for a dry pipe system, ayielding member exposed at one side to dry pipe pressure, a vent valve controlled by said yielding member and effective to y relieve the dry pipe pressure, a chamber at the opposite side of said member adapted to contain air under pressure, a passage normally open to connect the dry pipe system to said chamber and to thereby equalize the pressures on opposite sides of said yielding member, a second valve controlling said connecting passage to the dry pipe system, a cooperating port member for said-second valve, and means to effect relative movement of said second valve and its port member to close said connecting passage upon an abrupt drop in pressure in said dry pipe system,

such movement being independent of any movement of said yielding member.

78. In an air exhauster for a dry pipe system, a yielding member exposed at one side to dry pipe pressure, a vent valve controlled by said yielding member and efiective to relieve the dry pipe pressure, a chamber at the opposite side of said member adapted to contain air under pressure, a passage normally open to connect the dry pipe system to said chamber and to thereby equalize the pressures on opposite sides of said yielding member, a second valve controlling said connecting passage to the dry pipe system, a cooperating port member for said second valve, and means toefiect relative movement of said second valve and its port member to close said connecting passage upon an abrupt drop in pressure in said dry pipe system, said second valve and port member being supported on and movable with said yielding member.

In testimony whereof We have hereunto affixed our signatures.

GEORGE I. ROCKVOOD. HJALMAR G. GARLSON. 

